Reflectance Fourier Transform Infrared Spectroscopy Research Articles

Historical Silk: A Novel Method to Evaluate Degumming with Non-Invasive Infrared Spectroscopy and Spectral Deconvolution.

To correctly manage a collection of historical silks, it is important to detect if the yarn has been originally subjected to degumming. This process is generally applied to eliminate sericin; the obtained fiber is named soft silk, in contrast with hard silk which is unprocessed. The distinction between hard and soft silk gives both historical information and useful indications for informed conservation. With this aim, 32 samples of silk textiles from traditional Japanese samurai armors (15th-20th century) were characterized in a non-invasive way. ATR-FTIR spectroscopy has been previously used to detect hard silk, but data interpretation is challenging. To overcome this difficulty, an innovative analytical protocol based on external reflection FTIR (ER-FTIR) spectroscopy was employed, coupled with spectral deconvolution and multivariate data analysis. The ER-FTIR technique is rapid, portable, and widely employed in the cultural heritage field, but rarely applied to the study of textiles. The ER-FTIR band assignment for silk was discussed for the first time. Then, the evaluation of the OH stretching signals allowed for a reliable distinction between hard and soft silk. Such an innovative point of view, which exploits a "weakness" of FTIR spectroscopy-the strong absorption from water molecules-to indirectly obtain the results, can have industrial applications too.

Quantitative analysis of low content polymorphic impurities in canagliflozin tablets by PXRD, NIR, ATR-FITR and Raman solid-state analysis techniques combined with stoichiometry

Canagliflozin (CFZ) was a commercially new class of anti-diabetic drug, which had various anhydrate crystal forms and two hydrate crystal forms (Canagliflozin hemihydrate (Hemi-CFZ) and Canagliflozin monohydrate (Mono-CFZ) crystal form). Commercially available CFZ tablets’ active pharmaceutical ingredient (API) was Hemi-CFZ, which was easy conversion to CFZ or Mono-CFZ under the influence of temperature, pressure, humidity and other factors in tablets processing, storage, and transportation, thus affected bioavailability and efficacy of tablets. Therefore, quantitative analysis low content of CFZ and Mono-CFZ in tablets was essential to control tablets’ quality. The main objective of this study was to examine the feasibility of Powder X-ray Diffraction (PXRD), Near Infrared Spectroscopy (NIR), Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR) and Raman for quantitative analysis the low content of CFZ or Mono-CFZ in ternary mixtures. PLSR calibration models for low content of CFZ and Mono-CFZ were established by the solid analysis techniques of PXRD, NIR, ATR-FTIR and Raman combined with various pretreatments (such as Multiplicative Scatter Correction (MSC), Standard Normal Variate (SNV), Savitzky-Golay First Derivative (SG1st), Savitzky-Golay Second Derivative (SG2nd) and Wavelet Transform (WT)), and the correction models were verified. However, compared with PXRD, ATR-FTIR and Raman, NIR due to its water sensitivity was the most suitable for the quantitative analysis low content of CFZ or Mono-CFZ in tablets. Partial Least Squares Regression (PLSR) model for quantitative analysis low content of CFZ in tablets was as follow: Y = 0.0480 + 0.9928 X, R2 = 0.9986, LOD = 0.1596 %, LOQ = 0.4838 %, SG1st + WT pretreated. And that of Mono-CFZ were Y = 0.0050 + 0.9996 X, R2 = 0.9996, LOD = 0.0164 %, LOQ = 0.0498 %, MSC + WT pretreated and Y = 0.0051 + 0.9996 X, R2 = 0.9996, LOD = 0.0167 %, LOQ = 0.0505 %, SNV + WT pretreated, respectively. That can be used for quantitative analysis of impurity crystal content in drug production to ensure drug quality.

Multi-Analytical Characterization of Stone Relics from Meili Section of the Ancient Tea Horse Road in Yunnan, China

The stone relics in the Meili section of the ancient Tea Horse Road in Yunnan, China, are important for Sino-Tibetan cultural heritage. However, these relics were exposed to the risk of hydraulic erosion due to the construction of a hydroelectric power station, and thus protecting these relics is now imperative. Preliminary investigations and analyses of stone relics are crucial for their subsequent conservation and restoration. Thus, in this study, multi-analytical characterization including the microstructure, mineralogical characteristics, elements, and chemical compositions of the stone relics was conducted using optical microscopy (OM), scanning electron microscopy-energy dispersive spectrometry (SEM-EDS), polarized light microscopy, x-ray diffraction (XRD), and attenuated total reflection-Fourier transform-infrared spectroscopy (ATR-FTIR). In addition, the contaminants and pigments on the surfaces of the stone relics were identified and analyzed by Raman spectroscopy. OM, SEM and Raman spectroscopy indicated that the surface contaminants mainly comprised of moss and soil dust, and some of the stone relics exhibited porosity and weathering. Polarized light microscopy revealed that the mineralogical morphology of stone samples mainly appeared as allotriomorphic, hypidiomorphic, and colloform structures. ATR-FTIR, and XRD confirmed that the stone relics mainly consisted of quartz, muscovite, illite, and chlorite. In addition, Raman spectroscopic analysis showed that the pigments on the relic surfaces included chalk, barium white, langite, green earth, amorphous carbon black, chrome red, and chrome yellow. The findings of this study may provide scientific support for the conservation of the stone relics.

Modification of Cotton and Leather Surfaces Using Cold Atmospheric Pressure Plasma and TiO2-SiO2-Reduced Graphene Oxide Nanopowders

Surface modification of textile fabrics and leathers is very versatile and allows the products quality improvement. In this work, cotton and leather substrates were pre-treated with cold atmospheric pressure plasma (CAPP) and further coated with TiO2-SiO2-reduced graphene oxide composites in dispersion form. By using a Taguchi scheme, this research evaluated the effect of three significant parameters, i.e., the pre-treatment with CAPP, organic dispersion coating and TiO2-SiO2-reduced graphene oxide (TS/GR) composites, that may affect the morpho-structural properties and photocatalytic activity of modified cotton and leather surfaces. The characteristics of cotton/leather surfaces were evaluated by morphological, structural, optical and self-cleaning ability using scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDX), X-ray powder diffraction (XRD), attenuated total reflection-Fourier Transform Infrared spectroscopy (ATR-FTIR) and UV-Vis spectroscopy. The self-cleaning performance of the obtained cotton and leather samples was evaluated by photocatalytic discoloration of berry juice surface stains under UV light irradiation for 12 h. The successfulness of coating formulations was proven by the SEM analysis and UV-Vis spectroscopy. The XRD patterns and ATR-FTIR spectra revealed the cellulose and collagen structures as dominant components of cotton and leather substrates. The CAPP treatment did not damage the cotton and leather structures. The photocatalytic results highlighted the potential of TiO2-SiO2-reduced graphene oxide composites in organic dispersion media, as coating formulations, for further use in the fabrication of innovative self-cleaning photocatalytic cotton and leather products.

Ag/TiNPS nanocatalyst: biosynthesis, characterization and photocatalytic activity

Wastewater pollution by synthetic dyes has emerged as a serious environmental problem, causing a series of deleterious effects, since they have low biodegradability and considerable chemical stability, requiring advanced treatment technologies, such as Advanced Oxidative Processes (AOPs), such as heterogeneous photocatalysis. In this context, the present work aims to synthesize, characterize, and evaluate the photocatalytic activity of silver/titanium nanoparticles (Ag/TiNPs) using the biosynthesis method from Aloe vera extract for application in the removal of Rhodamine B dye (RhB) to propose an alternative to the problem of wastewater with dyes. Ag/TiNPs were characterized by N2 porosimetry (BET/BJ method), zeta potential (ZP), Field Emission Gun – Scanning Electron Microscope (FEG-SEM) and Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR). Ag/TiNPs showed SBET = 343 m2 g-1, Dp = 4.9 nm, Vp = 0.26 cm3 g-1, ZP = -15.1 mV and V-type isotherm with H1 hysteresis. ATR-FTIR showed the presence of characteristic functional groups of -OH, -C=O, -CH2, and -CH3. FEG-SEM micrographs presented a heterogeneous and porous surface with nanoparticle size around 12 nm. Regarding the heterogeneous photocatalysis, Ag/TiNPs showed 100% degradation of RhB (k = 0.0219 min-1) under visible irradiation after 120 minutes, with the possibility of reuse in 5 cycles and only 5% reduction in photocatalytic activity. Therefore, Ag/TiNPs showed promising characteristics for application as a nanocatalyst in the treatment of wastewater with dyes.

Discrimination of smokers and nonsmokers based on the analysis of fingermarks for forensic purposes

For decades, the unique characteristic ridge pattern of a fingerprint (FP) has been used as a mainstay for human individualization. Most recently, vibrational spectroscopic analysis of fingermark (FM) has attracted a substantial amount of attention in providing intelligence on personal traits. Particularly, extracting phenotypical information such as age and sex can be significantly beneficial in criminal investigation. However, chemical profiling of FMs using vibrational spectroscopy has been limited to age and sex determination, while other significant traits can also aid in narrowing down the suspect pool. In the current proof-of-concept study, attenuated total reflection Fourier transform-infrared (ATR-FTIR) spectroscopy combined with partial least squares-discriminant analysis (PLS-DA) have been employed for determining smoker from non-smoker donors from their FM residues. Genetic algorithm (GA) was applied to improve the discrimination rate of the developed model by selecting regions that are significant for the distinguish between the two classes. A subject wise leave-one-out cross-validation (LOOCV) was initially used to evaluate the performance of the binary PLSDA classifier for each donor. The binary model showed 84% correct classification at spectral level and 92% correct classification at donor level in subject wise LOOCV. In addition, receiver operating characteristic (ROC) curve analysis was constructed to establish a threshold for differentiating between the smoker and non-smoker FMs, this resulted in 100% accuracy at a donor level for external validation test. This preliminary study shows a great promise for identifying smoker donors from non-smoker individuals based on chemical analysis of FM residues. After fully developed, we believe the method will offer significant potential for real crime scene investigation due to its simplicity, non-destructive nature and its prospective for in-field analysis.

Desferrioxamine B: Investigating the Efficacy of Hydrogels and Ethanol Gels for Removing Akaganeite and Maghemite from Dry Wooden Substrates

Cultural heritage (CH) wooden artifacts are often stained by iron oxides/hydroxy-oxides, which may have detrimental effects on wood. Their removal is a common conservation practice, and it is usually achieved with non-eco-friendly chelators, such as ethylene diamine tetra acetic acid (EDTA) and diethylene triamine penta acetic acid (DTPA). Siderophores are green materials that have been recently explored as chelators, given the currently growing environmental concerns. This work investigated desferrioxamine B (DFO-B), a promising siderophore that has not been adequately studied for its potential in removing ferric oxides/hydroxy-oxides from dry CH wooden substrates. Mock-ups of maple (Acer platanoides L.) were artificially stained with akaganeite and maghemite, and DFO-B was employed via hydrogels (pH: 6.5 and 8.6) and ethanol gels. The chelator efficacy was assessed using Energy-Dispersive Spectroscopy (EDS), Attenuated Total Reflection–Fourier Transform Infrared Spectroscopy (ATR-FTIR), Scanning Electron Microscopy (SEM) and colorimetry. The hydrogels’ impact on the wood was also assessed using ATR-FTIR and colorimetry. The obtained results demonstrate that the most effective DFO-B formulation was the alkaline hydrogel (pH 8.6), followed by the acidic (pH 6.5) hydrogel and the DFO-B ethanol gel. No differences in wood chemistry or color were recorded when using pH 6.5 or 8.6. The DFO-B ethanol gels were also proven to be potential alternatives to hydrogels for use with water-sensitive CH substrates.

Unveiling the interaction mechanism between facet-dependent pyrite nanoparticles and Cr(VI) under anaerobic environment: adsorption, redox, and phase transformation

The environmental migration and bioavailability of Hexavalent chromium (Cr(VI)) could be affected by facet-dependent pyrite (FeS2) existing in soils and sediments. Conversely, the occurrence state of facet-dependent FeS2 might also be influenced by Cr(VI). However, the complex interactive mechanism at the solid–liquid interface between facet-dependent FeS2 and Cr(VI) still remained ambiguous. Herein, FeS2 nanobelts, FeS2 nanosheets, and FeS2 nanocubes with corresponding dominant facets of (−110), (001), (100)/(210) were prepared. The adsorption and reduction experimental results reflected that Cr(VI) species were predominantly adsorbed and a portion of them was reduced to Cr(III) at the FeS2 interfaces. In particular, the adsorption efficiency of Cr(VI) on (001) facet was 1.39 and 4.69 times than those on (−110) and (100)+(210) facets, respectively. The results of in situ Attenuated Total Reflectance Fourier Transform Infrared spectroscopy (ATR-FTIR) measurements and Density Functional Theory (DFT) calculations suggested that bidentate binuclear (BB) coordinated chromates were generated on the (001) facet while monodentate mononuclear (MM) coordinated chromates were formed on (−110), (100), and (210) facets. Due to the stronger adsorption energy and more stable coordination mode of BB for Cr(VI) species on (001) facet, FeS2 NS exhibited higher efficiency of Cr(VI) removal and reduction compared with FeS2 NB and FeS2 NC. In addition, partial FeS2 particles were proved to be transformed to goethite under the effect of Cr(VI). Owing to the stronger adsorption of Cr(VI) species on (001) facet, FeS2 NS also had a faster phase transformation rate than FeS2 NB and FeS2 NC. Above results all reflected the good structure–reactivity relationships between the FeS2 facets and the Cr(VI) removal efficiency as well as the phase transformation of FeS2 particles.

New Types and Dosages for the Manufacture of Low-Energy Cements from Raw Materials and Industrial Waste under the Principles of the Circular Economy and Low-Carbon Economy.

The cement manufacturing industry is one of the main greenhouse gas emission producers and also consumes a large quantity of raw materials. It is essential to reduce these emissions in order to comply with the Paris Agreement and the principles of the circular economy. The objective of this research was to develop different types of cement clinker blends using industrial waste and innovative design to produce low-energy cement. Several types of waste have been studied as alternative raw materials. Their main characteristics have been analyzed via X-ray fluorescence (XRF), X-ray diffraction (XRD), Attenuated total reflectance Fourier trans-form infrared spectroscopy (ATR-FTIR), thermal analysis (TG-DTG-DSC) and scanning electron microscopy and energy dispersive X-ray spectroscopy analysis (SEM-EDS). The results obtained from the experimental work carried out in this research focused on the study of crude blends for low-energy cement created from industrial waste. The effect of the addition of different industrial waste types, as a substitution for raw materials, in the production of low-energy cement with high dicalcium silicate content has been investigated. Thus, the dosage design has been performed using modified Bogue equations and quality indexes (LSF, AM, and SM). The calculations of both the modified Bogue equations and quality indexes necessitate knowledge of the weight percentages of CaO, SiO2, Al2O3, and Fe2O3, determined via XRF. In this theoretical design of the different blends, it has been established that a dicalcium silicate ratio of 60-65 wt % and an LSF of 78-83% as the limit are values common to all of them. The calculation basis for the crude blends has been based on calcined materials. Therefore, the chemical composition was established, following this premise. Thus, it was possible to develop cement clinker blends with compositions of 50 wt % and 100 wt % using industrial wastes. This research has shown that the clinkerization process is one of the main options for the valorization of waste and its consideration for inclusion as a raw material within the circularity of the cement industry's production process. Thus, waste is used as a raw material for the production of a more useful substance, taking into account the fundamental principles of the circular economy.

Modifications of the optical and vibrational properties in polylactic acid films by the addition of gold nanoparticles produced by laser ablation in chloroform

Gold nanoparticles (AuNPs) have been produced by laser ablation in chloroform and then embedded in polylactic acid (PLA) thus realizing PLA/Au nanocomposite films. Two initial volumes of chloroform of about 5 and 4 mL have been used, thus obtaining two different PLA/Au nanocomposite films. The effects of the embedded AuNPs into PLA films have been studied using Attenuated Total Reflectance Fourier Transform Infrared (ATR–FTIR) spectroscopy and ultraviolet/visible (UV–Vis) absorption spectroscopy. In the ATR-FTIR spectra, as AuNPs are embedded in PLA and their concentration grows up, the PLA characteristic vibrational features maintain their positions in wavenumber, but their IR absorption increases. This result confirms the presence of AuNPs in PLA and suggests that no strong chemical interaction occurs between PLA and AuNPs and no new bonds are formed. Concerning the UV–Vis optical properties an increase in the PLA optical absorption in the visible region has been also observed when AuNPs are embedded. The AuNPs presence is attested by the appearance of localized surface plasmon resonance (LSPR) absorption peak between 500 and 600 nm that shifts at longer wavelengths and broadens as the AuNPs concentration increases. The PLA absorption edge has been determined and its position in wavelength increases with increasing AuNPs concentrations. This observed absorption edge red shift indicates a decrease in the PLA band gap probably due to the electronic levels introduced by the embedded gold nanoparticles.

Operando DRIFT-MS for studying the oxidative steam reforming of ethanol (OSRE) reaction

An operando DRIFT-MS system (Diffuse Reflectance Infrared Fourier Transform Spectroscopy coupled with Mass Spectrometry) was designed and set up to study the oxidative steam reforming of ethanol reaction (OSRE). This reaction involves the mixture of water, ethanol and oxygen to produce mainly hydrogen, which is a rather attractive energy carrier. Spectroscopic monitoring of the process is a key tool to contribute to the understanding of: i) the dynamics on the catalyst surface, ii) the reaction mechanism and iii) the effect of the solid's properties on the catalytic process. In this sense, this document sets forth the experimental design that allows to carry out the study under operando DRIFT-MS conditions through time for the OSRE reaction. Selection criteria for parameters, materials, configuration, and experimental conditions are included, particularly optimizing the parameters of particle size and the dilution factor with KBr as well as the temperature and flow conditions for carrying out the reaction.•Clear signals of the adsorbed species in IR that do not present interference by water in the reaction atmosphere.•Simple assembly and online product detection by MS that allow to follow the change in the products of the OSRE reaction according to the temperature.•Controlled entry of gases and quantification by loop injection.

Development of a rapid detection protocol for microplastics using reflectance-FTIR spectroscopic imaging and multivariate classification

Reflectance-FTIR spectroscopy provides opportunities for faster, more automated, and cheaper detection of microplastics in the environment.

Metasurface-enhanced infrared spectroscopy in multiwell format for real-time assaying of live cells.

Fourier transform infrared (FTIR) spectroscopy is a popular technique for the analysis of biological samples, yet its application in characterizing live cells is limited due to the strong attenuation of mid-IR light in water. Special thin flow cells and attenuated total reflection (ATR) FTIR spectroscopy have been used to mitigate this problem, but these techniques are difficult to integrate into a standard cell culture workflow. In this work, we demonstrate that the use of a plasmonic metasurface fabricated on planar substrates and the probing of cellular IR spectra through metasurface-enhanced infrared spectroscopy (MEIRS) can be an effective technique to characterize the IR spectra of live cells in a high-throughput manner. Cells are cultured on metasurfaces integrated with multiwell cell culture chambers and are probed from the bottom using an inverted FTIR micro-spectrometer. To demonstrate the use of MEIRS as a cellular assay, cellular adhesion on metasurfaces with different surface coatings and cellular response to the activation of the protease-activated receptor (PAR) signaling pathway were characterized through the changes in cellular IR spectra.

Enzymatic surface modification of banana fabric with cellulase: Characterization and antimicrobial finishing with plant extracts

The current study examined the effect of cellulase enzyme bio-scouring on the banana fabric and the improvement in the antimicrobial property of the same fabric with the natural plant-based extract. Pre-treatment of banana fabric with cellulase enzyme was optimized with different parameters, namely enzyme concentration (2%), pH (5.5), MLR (Material to Liquid Ratio) (1:20), time (60 min), and temperature (55 °C). Effect of the enzyme bio-scouring on surface properties was studied using characterization techniques such as Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) Spectroscopy, Scanning Electron Microscopy (SEM), X-Ray Photoelectron Spectroscopy (XPS), Wet-out time, Water contact angle and Hydrophilicity test. The changes in bulk properties due to the enzymatic treatment were studied by Weight Loss (%), X-Ray Diffraction (XRD), Thermal Attenuated Gravimetric Analysis (TGA), and Tensile Strength Measurement. The ATR-FTIR spectroscopy and XPS characterization revealed enhancement in the concentration of polar functional groups like -CHO, -COOH, -OH on the surface of the cellulase-treated banana fabric. For the antimicrobial finish, leaf extracts of Camellia sinensis (Green Tea) and Ocimum sanctum (Tulsi) were applied to cellulase-treated banana fabric in different percentages, coupled with citric acid as a cross-linking agent. Antimicrobial testing was done using the Agar plate method and the altered Hoenstein test against one gram-positive bacteria (Staphylococcus aureus) and one gram-negative bacteria (Escherichia coli). In the case of cellulase enzyme treated banana fabric, 97% reduction for S. aureus and 92% reduction for E. coli were achieved. The durability of the finish was tested, and the antimicrobial finish persisted up to three cycles of washing in the case of the cellulase enzyme-treated banana fabric. In contrast, the antimicrobial finish was lost after the first washing of untreated fabric. According to the findings, the cellulase enzyme treatment can be used as an environmentally acceptable method for improving surface properties and adsorption of the antimicrobial extracts, thereby enhancing the antimicrobial property of the banana fabric. • Value addition to banana fabric-a natural cellulosic fabric derived from commodity crops' byproducts/waste. • Cellulase enzyme pre-treatment of banana fabric and its effect on the surface and bulk properties. • Characterization of treated fabric with advanced techniques and optimization of process parameters. • Antimicrobial finishing of enzyme-treated banana fabric with natural extracts Camellia sinensis and Ocimum sanctum . • Enhanced uptake/better durability of finishing: Sustainable approach for improving competitiveness and market potential of banana fabric.

The colours of Segesta. Searching for the traces of the lost pigments

• Non invasive, multianalytical approach and in situ analysis for the investigation of traces of pigments. • Optical microscopy, UV-fluorescence, XRF and FORS spectroscopy for the analysis of traces of pigments. • Interchangeability of XRF and FORS for identification of general type of pigments polychromy of Greek temples. • Example of fruitful cooperation between chemists, archaeologists and the public institutions for the safeguarding of archaeological heritage. Many monuments and objects of the ancient civilizations were painted, but unfortunately the pigments are not still present and sometimes only small traces are evident. The analysis of the traces requires a multianalytical approach through the use of non-invasive techniques and only if necessary of a microsampling. Here, the study of the traces of colours found in some architectural elements and findings belonging to the Archeological Park of Segesta (Trapani, Italy) is reported. The traces are identified and characterised via several techniques such as Optical Microscopy, UV-Fluorescence Imaging, Fiber Optical Reflectance Spectroscopy (FORS), X-ray Fluorescence (XRF) and FT-IR Spectroscopy. Various pigments were identified, some of which are no longer clearly visible to the naked eye: hematite, umber, vegetable black and bone black. Despite the small amount of detectable pigment, the performed investigations allowed us to define part of the pictorial palette to imagine and relive the past in one place.

Multiblock poly(ether-b-amide) copolymers comprised of PA1212 and PPO-PEO-PPO with specific moisture-responsive and antistatic properties

Functional multiblock poly(ether-b-amide) (PEBA) copolymers, comprised of PA1212 (polyamide 1212) as hard segments and Jeffamine ED-2003 as soft segments, were successfully prepared via two-step melt polycondensation without any amidation catalyst. Here, using diamino-terminated poly(propylene oxide)-poly(ethylene oxide)-poly(propylene oxide) (PPO-PEO-PPO), Jeffamine ED-2003, enhances the compatibility between polyamide oligomer and polyether, which is better than the traditional route using hydroxyl-terminated polyether. The chemical structure of multiblock PEBAs, as well as the microphase separated structure with crystalline phase of polyamide and polyether, were confirmed by heteronuclear multiple-bond correlation spectrum, heteronuclear multiple quantum correlation spectrum, Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry and dynamic mechanical analysis. The hydrophilic PEBA copolymers showed water adsorption ranging from 87.3% to 17.1% depending on the polyether content, and specially showed moisture responsive behavior within seconds when exposed to moisture. The corresponding mechanism was studied using time-resolved attenuated total reflectance FT-IR spectroscopy in the molecular level and the water diffusion coefficient was estimated to be 1.07 × 10–8 cm2∙s–1. Two-dimensional correlation FT-IR spectra analysis was performed to confirm that the interaction between water and polyether phase was in preference to that between water and polyamide matrix, and water molecule only forms hydrogen bond with the polyether segment. Due to the incorporation of PEO segments, the PEBAs have the surface resistivity varying from 5.6 × 109 to 6.5× 1010 Ω, which makes PEBA potential candidate as permanent antistatic agent.

Synthesis, Characterisation and Catalytic Evaluation of Castor Oil-Templated Mesoporous Sulfated Solid Acid Catalysts for Esterification Reaction

In bio-refinery and other catalytic reactions, heterogeneous catalysts confer advantage over homogenous catalysts due to minimized recovery and separation costs. However, templating surfactant and solid support for the synthesis of heterogeneous catalysts ought to consider their cheap sources and environmentally friendliness for their sustainable use. Thus, with the vision to make the process significantly benign, in the present work, solid acids were synthesised from renewable sources (castor oil as surfactant and rice husk as the source of silica). The synthesised castor oil-templated mesoporous sulfonic acid modified catalysts (SO3H-MTS and SO3H-MT-RHS) were characterised and evaluated for catalytic esterification of acetic acid (C2), hexanoic acid (C6), lauric acid (C12), palmitic acid (C16), and ricinoleic acid (C18) with butanol at 110 °C. Physicochemical properties of the synthesised materials were characterised by nitrogen porosimetry, X-ray powder diffraction, thermogravimetry, X-ray Photoelectron Spectroscopy (XPS), and Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS). The porosimetric analysis of the synthesised materials revealed a type IV adsorption-desorption isotherm reminiscent of the mesoporous structures. The surface area of the synthesised materials decreased upon functionalisation by sulfonic group. The DRIFTS and XPS confirmed the attachment of sulfonic functional group on the synthesised materials. Evaluation of the catalytic performance of the synthesized materials was determined through analysis of carboxylic acid conversions using gas chromatographic technique. SO3H-MTS gave higher acid conversions compared to SO3H-MT-RHS. The sulfated solid acid catalysts showed good catalytic activity on the esterification with conversion ranging from 96-37% for C2-C18 with butanol at 110 °C within 6 h. Such castor oil-templated mesoporous sulphated solid acid catalysts can therefore be applied in biodiesel production upon process optimisation.

Facile fabrication of ceramic-polymeric nanocomposite membrane with special surface wettability using amino decorated NH2-SiO2@SiC nanopowder for production of clean water from oily wastewater

Given the huge market potential of treating oily wastewater, a ceramic membrane with special surface wettability was fabricated by covalently decorating amino-functionalized silicon carbide (NH2-SiO2@SiC) as an active layer on alumina support. The NH2-SiO2@SiC was synthesized by growing a layer of silicon dioxide (SiO2) on silicon carbide (SiC) leading to silicon dioxide loaded silicon carbide (SiO2@SiC). Then amino (-NH2) functionalization of SiO2@SiC was carried out through 3-triethoxysilylpropylamine (APTES) yielding NH2-SiO2@SiC. The NH2-SiO2@SiC was covalently deposited as active layer on alumina support through interfacial polymerization with terephthaloyl chloride (TPC) leading to SiO2@SiC/polyamide nanocomposite decorated on alumina (SiO2@SiC/PA@Al2O3) ceramic membrane. The SiO2@SiC/PA@Al2O3 ceramic membrane was thoroughly characterized by several membrane characterization techniques including water and oil contact angles, SEM (scanning electron microscopy), elemental mapping, EDX analysis (energy dispersive x-ray) and ATR-FTIR (Attenuated Total Reflectance Fourier Transform Infrared spectroscopy). The SiO2@SiC/PA@Al2O3 ceramic membrane was applied for sepraration of surfactant stabalized oil-in-water (O/W) emulsion feed. The effect of increasing O/W emulsion concentration (33.75–250 ppm) was studied by varying the amount of oil in the emulsion. The ceramic membrane was able to maintain a separation efficiency of > 98 % with permeate flux of 270 L/m2.h at a transmembrane pressure of 2 bar. The long-term filtration tests revealed that SiO2@SiC/PA@Al2O3 ceramic membrane retained its separation efficiency at > 98 % for 420 min when 125 ppm O/W emulsion was used as feed. The SiO2@SiC/PA@Al2O3 ceramic membrane showed a potential of treating a high concentration (250 ppm) surfactant stabalized O/W emulsion.

Modeling changes in chocolate during production and storage by ATR-FT-IR spectroscopy and MCR-ALS hybrid soft and hard modeling

Industrially tempered dark chocolate processed under different conditions was analyzed using Attenuated Total Reflection-Fourier Transform-Infrared spectroscopy (ATR-FT-IR). Spectra were collected during the cooling process right after tempering using two distinct machines and machine operational modes and over short and long storage (1 day and two months, respectively). To interpret the spectra collected, Multivariate Curve Resolution-Alternating Least Squares (MCR-ALS) analysis was used. MCR-ALS incorporated a dedicated implementation of hard modeling constraints for the elucidation of the spectral and concentration profiles of chocolate contributions during the monitored process with the aim of reducing ambiguity in the data interpretation. Thus, the spectral signature of the amorphous form of chocolate was constrained to follow a Gaussian shape, in line with previously reported works and with measurements observed at the beginning of the cooling process. Additionally, hard modeling constraints were applied to the concentration profiles linked to the cooling process by implementing the Avrami kinetic model, often postulated to describe thermally induced fat crystal transformations. The application of the hard modeling constraints eased the generation of interpretable solutions and resulted in concentration profiles and spectral signatures that were defining much better the crystal state of the chocolate samples. A two-component system explained the studied procedures, with a contribution S1 representing the highly crystalline state of the chocolate fats and S2 representative of the amorphous/less stable state. In general, we were able to track the transition from a less ordered to a highly ordered crystal state of the fats during the cooling stage of chocolate. After short storage, the chocolates had contributions of both S1 and S2 profiles. After long storage, the S1 crystalline form was the most dominant interpreted as the reorganization of the triglyceride acyl chains towards a thermodynamically favorable state. The latter was observed for all analyzed chocolates, implying that, regardless the tempering process or temper regime tested, the fats in chocolates reach the same high crystalline state after maturing.

Zinc oxide nanoparticles: Biosynthesis, characterization, biological activity and photocatalytic degradation for tartrazine yellow dye

The present study aims to synthesize/characterize zinc oxide nanoparticles (ZnO-NPs) to evaluate the application of tartrazine yellow (TY) dye removal. ZnO-NPs were synthesized by the biosynthesis method from Eucalyptus grandis extract. X-ray diffraction (XRD), zeta potential (ZP), N2 porosimetry, Field Emission Gun Scanning Electron Microscope (FEG-SEM), zero charge point (pHZCP) and Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR) were used to the ZnO-NPs characterization. The antimicrobial activity was performed by the MIC (Minimum Inhibitory Concentration) method against gram-positive (S. aureus) and gram-negative (E. coli, K. pneumoniae and P. aeruginosa) strains. For cellular activity assays, MTT (3-(4,5-Dimethylthiazol-2-yl) and DCFH-DA (2′7′ dichlorofluorescein diacetate) tests were performed with cell lines of the 293T, A549 and U87MG. FEG-SEM micrography indicated a heterogeneous and porous morphology with rod-shaped zinc oxide nanoparticles (particle size ranged from 40 to 50 nm). ZnO-NPs showed a negative charge surface (−11.6 ± 0.2 mV), pHZCP ≈ 7.16 with type III and H1 hysteresis (SBET = 3.9 m2/g, and Dp = 16.2 nm) indicating a mesoporous material with pores open at both ends. The optimal condition was [ZnO-NPs] = 0.6 g/L, [TY] = 20 mg/L and pH ≈ 6.0 with 76.1 % (k = 0.0077 min−1) for the TY photodegradation under visible radiation, and after VI cycles of ZnO-NPs recycling, there was a decrease of only 6 %. ZnO-NPs showed antimicrobial activity of 0.625 mg mL−1, as well as a decrease in cell viability in the three tested lines in 100 and 300 µg mL−1. Therefore, ZnO-NPs showed potential application for TY photodegradation to be used in wastewater treatment and nanomedicine.